Tool holder for clamping inserts, using a resilient L-shaped clamp

ABSTRACT

Tool holder device has an elongated main body presenting a rearwardly extending back portion (2) to be received inside a turret body groove and locked therein by means of wedge means and a forwardly extending portion (3) having an obliquely arranged abutment surface (4) and an outwardly facing surface (5) defining a seat for the insert tool holder. The adjoining surface (6) of the main body having an elongated groove (7) having parallel walls also in parallel with the outwardly facing surface and a bottom perpendicular to same surface and in an intermediary position a number of threaded bores (8) extending essentially in parallel with the outwardly facing surface (5). The groove being adapted to receive two or more L-shaped clamping pieces (9) having one leg (10) with an end portion with a thickness corresponding to the width of the main body elongated groove (7) and another leg (11) having an abutment surface (12) for engaging the insert holder. Each clamping piece (9) includes through bores (13) for screws essentially in parallel with the leg 10 and an adjoining abutment surface for the screw head. The clamping piece in a transition portion (15) between its two legs having a mutual bending facilitating recess or groove (16).

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates to a tool holder or clamping piece for insertholders, and, more particularly, to a tool holder is clamped in a seatat the turret with the insert holder which in the tool holder.

2. Description of the Prior Art

A known clamping piece or tool holder has a base part with abutments forclamping wedges and screws for securing the base part in grooves at theturret body. A carrier piece for the tool or insert holder which laterpiece as also the base piece has complementary guiding and positioningportions, on securing the pieces to each other engaging each other andlocalizing the parts as well as at the carrier piece arranged setableand adjustable guides for clamping bodies pressing the tool holdertowards an abutment.

Another known device includes a tool holder made in one piece with arear protruding portion intended to be wedged inside the turret bodygroove and having an elongated clamping rail intended to secure the toolholder by means of screws passing through holes in the rail and insertedinto the holder body. A opposite edge of the holder abutting a seat onthe holder.

DE, A1 3 434 089 and GB, B 19851/1909 disclose arrangements for securingparting tool holders and tools by means of an essentially L-shapedclamping piece one leg of which rests in an elongated groove at the basepart whereas the other leg engages a tool holder or tool in order topress same against a seat when pressed towards the base part by means ofone or more screws. The former publication also reveals a weakening slotmade in the leg of the clamping piece engaging the elongated groove tofacilitate the movement of the other leg towards the tool holder. Thelater publication discloses a rigid L-shaped clamping piece. Uponturning the screw, the clamping piece is swung around an axis at theline of engagement along the base part groove. The corresponding axis ofthe weakened leg clamping piece follows the bottom of the weakeninggroove. The positioning of the axes below a plane perpendicular to theplane of the tool holder and passing the point or line of engagement atthe free edge of the tool holder implies that any force exerted towardsthe tool holder engaging leg of the clamping piece will result in adivision of the force acting against the tool holder edge in onecomponent acting in the plane of the tool holder and one componentpushing outwardly so as to remove the holder from its seat.

DE, B2 2 548 870 and U.S. Pat. No. 4,545,705 disclose arrangementssimilar to the one shown in GB, B 19851, i.e. clamping pieces having oneleg resting in a groove and the other leg engaging a tool holder ortool. In all cases, the clamping piece swings around an axis situatedwell below a plane through the upper edge of the tool or tool holder.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a novel tool holderhaving a simple construction and easily manufactured without complicatedmachining and the like. Another object is to fulfill a long felt need offacilitating the change of tool holders without necessitatingdismantling of a multitude of pieces.

Still another object is to provide such a tool holder device arrangedwith the contact directions of the clamp piece securing as stable aspossible a clamping of the tool holder.

The tool holder according to this invention includes an elongated mainpart having a rearwardly extending back portion insertable into theturret body recess and a forwardly protruding portion. The forwardlyprotruding portion having an obliquely located abutment surface togetherwith a joining outwardly facing surface for positioning the insertholder. The opposite edge of the outwardly facing surface is joined witha backwardly obliquely arranged surface in turn passing into anelongated groove. The elongated groove having parallel walls alsoparallel with the outwardly facing surface and a bottom at right angleswith the outwardly facing surface. The portion of the main port havingthe rearwardly obliquely arranged surface includes a number of threadedbores which are essentially parallel with the outwardly facing surface.

At the main part, there are mountable two or more essentially L-shapedclamping pieces. Each clamping piece having a non significant lengthdimension and having first leg with one end portion having a thicknessclosely corresponding to the width of the elongated groove in the mainpart and second leg having an oblique inner abutment face. Each clampingpiece also having at least one through hole essentially parallel withthe first leg and having an adjoining abutment surface for the head of ascrew which surface is obliquely arranged so that a screw passed throughthe bore and into one of the threaded bores in the main part will engageessentially only at the portion of the abutment surface closest to theleg end having the obliquely arranged surface.

The clamping pieces have at the transition where the two legs are joineda recess facilitating the bending of the material.

BRIEF DESCRIPTION OF THE DRAWINGS

One preferred embodiment of the device according to this invention willbe described in detail with reference to the accompanying drawing, inwhich

FIG. 1 is a side elevational view of the tool holder main part as seenfrom the outside,

FIG. 2 is an end elevational view of the main part,

FIG. 3 is a front elevational view of a clamping piece,

FIG. 4 is a cross sectional view of the clamping piece, and

FIG. 5 is an end elevational view of the clamping piece mounted on themain part with an insert holder held thereby.

DETAILED DESCRIPTION OF THE INVENTION

The main part, i.e. the tool holder 1, is formed of a piece of steelthrough milling or the like machining to a given specific shape.

The part 1 includes at the rear end, i.e. on the side which, in mountedposition, will be facing the turret body, an elongated extending portion2 forming a specific portion to be inserted into a groove (not shown) inthe turret body (not shown) and secured therein by well known wedgingmeans (not shown) inserted between the extending portion and theopposite wall of the groove.

The front side of the main part 1 has at the lower portion thereof anelongated projection 3 having a downwardly and inwardly inclined upperedge 4 serving as an abutment for an insert holder S (FIG. 5) placedthereon. A front face 5 adjoins upper edge 4 and defines together withit two sides of a seat for the insert holder S. The front face 5 changesover into a rearwardly and downwardly inclined surface 6 which inclinestowards a longitudinal groove 7 arranged in the upwardly facing side ofthe main part 1. The groove has sides parallel with the front face 5 anda bottom essentially at right angles with the sides. The main part 1also includes at least two threaded bores 8 (only one shown) extendingessentially parallel with the front side 5 from the inclined surface 6.

To the main part 1 are attached at least two clamping pieces designated9. Each clamping piece is an inverted essentially L-shaped piece ofmaterial having insignificant length and preferrably manufactured bymachining rod material into desired sectional shape and subsequentcutting in needed lengths.

Each clamping piece 9 has a downwardly directed first leg 10 having athickness A closely corresponding with the width B of the longitudinalgroove 7. The engagement between the first leg 10 and the groove ensuresa secure positioning of the clamping piece 9.

A second leg 11 extends from the first leg 10 and has at the undersideof its outer end an obliquely arranged surface 12 which serves ascontact surface for the insert holder S and also presents a bore 13essentially parallel with the first leg 10. The bore 13 is connected toa counter sunk seat or abutment portion 14 for receiving the head of ascrew (not shown) which is threaded through the bore 13 into any one ofthe threaded bores 8 of the main part 1. This counter sunk seat 14 isobliquely arranged so that a portion 14a thereof adjacent an outer endof the second leg 11 is higher and consequently will meet the head ofthe screw first and serve as abutment for the same.

In a transition portion 15 between the two legs 10 and 11 there is anobliquely arranged recess or slot 16 which gives to the two legs amutual mobility.

After securing the main part 1 of the tool holder in a known way in theturret body groove, the insert holder S can be mounted therein. Thistakes place by placing the insert holder S with the lower side thereoftowards the lower obliquely arranged edge 4 and engaging the frontsurface 5. Each clamping piece 9 is secured in desired position alignedwith one of the bores 8 by inserting its first leg 10 into the groove 7and threading its associated screw 17 (FIG. 5) into the bore. As soon asa screw head reaches the front portion 14a of the counter sunk seat 14,the upper leg 11 will deflect via the transition portion 15 between thetwo legs whereby the obliquely arranged surface 12 will contact theinsert holder S and press the same downwardly towards the oppositeabutment 4 and simultaneously inwardly towards the surface 5. The morethe screw 17 is tensioned, the more the leg 11 will deflect downwardly.To permit this movement, the bore 13 for the screw is so shaped that thescrew shaft will run freely therethrough even if the upper leg 11 isdeflect of its original position.

By arranging a recess 16 in the transition portion 15 between the twolegs 10 and 11, there is achieved a hinge function. The pivot axisthereof will be situated at a rather high level and this results in anefficient pressing action towards the insert holder S. This is theresult of the lever relations existing where the fulcrum of the onearmed lever, i.e. the transition portion 15, will be situated higherthan a normal plane perpendicular to the upper edge of the insert holderand the contact surface 12 at the end of the leg 11. The force resultingfrom the lightening of the screw 17 and acting at the contact pointbetween the end of the leg 11 and the insert holder S may be divided inone component parallel with the plane of the insert holder S and thefront face 5 and one inwardly directed component perpendicular thereto.Consequently, on tightening the screws, the insert holder S will bepressed downwardly towards the abutment surface 4 and simultaneouslyagainst the front face 5 of the main part 1.

The invention is not restricted to the above described embodiment butmay be modified within the scope of the attached claims.

I claim:
 1. A tool holder for receiving an insert holder, the toolholder comprising:(a) a main part providing a seat for an insert holderincluding one rigid abutment surface for engaging a first surface of theinsert holder and a lateral abutment surface for engaging a secondsurface of the insert holder, said main part is provided with anelongated groove spaced from said seat and, along said elongated groove,a plurality of bores dimensionally sized for receiving force applyingscrews; (b) at least one clamping piece engageable with a third surfaceof the insert holder opposite the first surface, said at least oneclamping piece being substantially L-shaped having a first leg, a secondleg and a transition portion between said first and second legs, saidfirst leg rigidly received in said elongated groove, said second leghaving a bore for a force applying screw and a free end presenting acontact surface for the third surface of the insert holder, saidtransition portion having a bend enhancing recess defined therein toenhance mutual bendability of said first and second legs relative toeach other, said bore for a force applying screw in said second leghaving a surrounding counter sunk seat intended to form an abutment fora head arranged on a force applying screw, said counter sunk seat beinginclined relative to a center axis of said bore for a force applyingscrew in order to allow concentration of force from a force applyingscrew on a portion of said counter sunk seat adjacent said free end ofsaid second leg presenting said contact surface; and (c) a forceapplying screw extending through said bore to engage one of saidplurality of bores, said force applying screw having a head engagingsaid counter sunk seat whereby, upon tightening of said force applyingscrew, said second leg deflects at said transition portion so that saidcontact surface engages the third surface of the insert holder with aforce acting both towards said rigid abutment surface and towards saidlateral abutment surface.
 2. The tool holder according to claim 1,wherein said counter sunk seat is obliquely arranged relatively to acenter axis of said bore for said force applying screw so that saidportion thereof adjacent said free end of said second leg initiallyengages said head of said force applying screw as said force applyingscrew is tightened.
 3. The tool holder according to claim 2, whereinsaid contact surface of said second leg for engaging the third surfaceof the insert holder is obliquely arranged.
 4. The tool holder accordingto claim 1, wherein said contact surface of said second leg for engagingthe third surface of the insert holder is obliquely arranged.
 5. A toolholder according to claim 1, wherein said contact surface and saidtransition portion with said bend enhancing recess of said at least oneclamping piece are relatively positioned to create an effective bendingfulcrum for said second leg situated to produce the force acting bothtowards said rigid abutment surface and towards said lateral abutmentsurface.
 6. A tool holder according to claim 1, wherein said countersunk seat is obliquely arranged relative to said center axis of saidbore for said force applying screw so that said portion of said countersunk seat which receives the concentration of force from said forceapplying screw is higher than remaining portions of said counter sunkseat and contacts said force applying screw first to provide an abutmentfor said force applying screw.
 7. A tool holder according to claim 1,wherein said portion of said counter sunk seat which receives theconcentration of force from said force applying screw is located betweensaid center axis of said bore for said force applying screw and saidfree end of said second leg presenting said contact surface.
 8. A toolholder according to claim 1, wherein said insert holder corresponds inthickness to said rigid abutment surface of said main part.